The purpose of this project is to support in part the EORTC Data Center and Coordinating Office in Brussels, managed by M. Staquet, M.D., M.S., Clinical Coordinator of EORTC. The EORTC Data Center is a service organization for all clinical cooperative groups of EORTC. It conceives and organizes multicenter trials and collects and analyzes trial data which are made available to NCI whenever requested (more than 100 multi-center trials in progress in 1983). The Data Center has also a coordinating function between European and U.S. centers and more specifically with NCI. It plays a central role in the trials performed with NSC drugs not tested in the U.S. For this project, collaborative planning and programming with NCI are being done by the Data Center. Finally, the EORTC Data Center has its own research program in applied statistics, methodology of clinical trials, and clinical research.